title: Isolation of spermatozoa with low levels of fragmented DNA with the use of flow cytometry and sorting.
abstract: OBJECTIVE
  To develop a method to select spermatozoa with low DNA fragmentation rates for assisted reproduction technologies (ART).
  
  
  METHODS
  Multistep prospective cohort study.
  
  
  METHODS
  University hospital.
  
  
  METHODS
  Semen samples of 34 infertile men were prepared in parallel with swim-up and fluorescence-activated cell sorting (FACS), and 11 semen samples were used for testing the staining strategy.
  
  
  METHODS
  Flow cytometric sorting of YO-PRO-stained spermatozoa.
  
  
  METHODS
  Assessment of recovery of spermatozoa and purity after sorting, quantification of sperm DNA fragmentation and viability after sorting and after swim up preparation.
  
  
  RESULTS
  Staining with YO-PRO could be performed successfully in regular culture medium, both dead and apoptotic spermatozoa were labeled without the dye entering the viable spermatozoa. Compared with the conventional swim-up method, the sorted viable population showed a significantly reduced number of spermatozoa with fragmented DNA.
  
  
  CONCLUSIONS
  A novel method has been developed, which not only might improve the outcome of ART, but can also help to clarify the ongoing controversy of the role of DNA fragmentation in male infertility.
authors.affiliation: Clinic of Gynecological Endocrinology and Reproductive Medicine, University of Basel, Basel, Switzerland.
authors.forename: Sofia C
authors.initials: SC
authors.lastname: Ribeiro
authors.forename: Gideon
authors.initials: G
authors.lastname: Sartorius
authors.forename: Flurina
authors.initials: F
authors.lastname: Pletscher
authors.forename: Maria
authors.initials: M
authors.lastname: de Geyter
authors.forename: Hong
authors.initials: H
authors.lastname: Zhang
authors.forename: Christian
authors.initials: C
authors.lastname: de Geyter
mesh_terms: D000328:Adult; D017209:Apoptosis; D002469:Cell Separation / Q000379:methods*; D002470:Cell Survival; D015331:Cohort Studies; D053938:DNA Fragmentation; D005434:Flow Cytometry / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013094:Spermatozoa / Q000166:cytology*; D055815:Young Adult
keywords: DNA fragmentation; FACS; Spermatozoa; TUNEL; apoptosis